Natalie Portman played a ballerina in the grip of psychological trauma in "Black Swan", but the Israeli actress said she had lots of support while directing her first film, about the childhood of Israeli intellectual Amos Oz, shown in Cannes.

Portman both directs and stars in "A Tale of Love and Darkness", based on Oz's autobiographical novel of the same name focusing on his relationship with his mother Fania, who committed suicide when Oz was 12.

Oz's mother, played by Portman, was a Polish Jewish refugee from a moneyed family who felt lost in the poverty and violence in Jerusalem during the period surrounding the formation of the Israeli state in 1948.

In Portman's movie, she yearns for the forests of her childhood and spins fabulous tales to entertain her son, until despair totally darkens her life "It's been a really incredible experience," Portman told Reuters in an interview on Sunday, talking about the making of the film which garnered mixed reviews after its screening out of competition at the Cannes International Film Festival.

"It's been really challenging but I think that every challenge has helped me grow more and luckily I've had many people around me - my family, my friends and my crew who helped me so much throughout that I felt so well supported that it was never an existential crisis during it."

Trade publication Variety called the result a "drearily empathetic" film that would rely on Portman's star power to sell it, while Britain's Guardian called it "a serious, well-made adaptation" of the book.

Asked why she had wanted to direct a film, she said: "The way to feel alive is to change and to try new things, to stimulate yourself, to be afraid, do things you're afraid of." Portman said adapting Oz's novel brought the actress closer to the writer and intellectual, who is one of the darlings of the Israeli left and a longtime supporter of the two-state solution for the Israeli-Palestinian conflict.

"I've gotten to know him more and more throughout the process. Now I feel like family.

"I've played his mother, in a way, so in a strange way it feels like he's my child and I'm so proud of him," she said. Over the past 20 years, Portman has appeared in films such as "v for Vendetta", "Thor" and "Star Wars", and won an Academy Award for her role in "Black Swan".